Here's some "cut and pastes" from various sources to give a brief description about oils. I think it is factual and informative without being biased... <br /><br /> Oil Terminology: <br /><br />Organizations: <br /><br />NMMA National Marine Manufacturers Association<br /><br />BIA Boating Industry of America<br /><br />API American Petroleum Institute<br /><br />JASO Japanese Automobile Standards Organization<br /><br />ISO International Standards Organization<br /><br />TCW - Two Cycle Water-cooled. Typically, outboard motors.<br /><br />TC-A - Two Cycle Air-cooled. Typically, chainsaws, motorscooters, lawn & garden equipment, generators, etc.<br /><br />Base Oils - Refined oil from which the specific finished oil starts with. The base oil provides proper viscosity, resists deposit formation during exposure to extreme heat & maintains good flow properties.<br /><br />"Ultra-Clean" Oil - Base oil that has been refined to an extreme degree to remove small particles & contaminants that remain in the typical base oil.<br /><br />Additive Package - Bolsters the base oils performance to provide specific functions beyond the base oils capability. Keeps engines clean by preventing ring sticking, piston deposits, plug fouling & exhaust deposits. Additives reduce smoke, prevent wear & prevent corrosion. <br /><br />Dispersant (solvent) - Provides good flow & mixing properties at low temperatures. Evaporates & burns cleanly with gasoline. <br /><br />Ash - Additive, typically metallic, used in air-cooled 2-cycle engines. Helps to dissipate the high heat in air-cooled engines. <br /><br />Viscosity - The measurement of a fluids resistance to flow. The ability to maintain consistency and avoid breakdown.<br /><br />Lubricity - The ability of an oil or grease to lubricate. Also called "film strength". <br /><br />2-Cycle (2T) Oils:<br /><br />Differences Between TC-W & TC-A: <br /><br />Governing Organizations: <br /><br />Outboard Engines NMMA<br /><br />All other 2-Strokes API, JASO & ISO<br /><br />TC-W: This type of oil is to be used for water-cooled 2-Stroke Outboard Engines. Incorporates use of "ashless" dispersants in additive package to prevent formation & accumulation of ash deposits in piston crowns, combustion chamber & piston rings. Formulation must be ashless due to lower running temperature of a water-cooled engine. <br /><br />TC-A: This type of oil is to be used for air-cooled 2-Stroke Engines. Typically chainsaws, lawn & garden equipment, lawn mowers, motorscooters, etc. This oil incorporates an "ash" dispersant, typically metallic. This helps cool the combustion chamber from ultra-high temperatures at which these air-cooled engines run. <br /><br />Evolution of TC-W3:<br /><br />According to the NMMA, almost all engine failures can be traced back to fuel quality, not manufacturing defects or oil quality problems. Marine Engine Manufacturers needed to reduce warranty costs. When the Marine Engine Manufacturers found that they could not get cooperation from the gasoline manufactures, nor help in quality control from them, the engine manufacturers had special oils developed to counteract the bad effects from low quality fuels. Thus, BIA, and subsequently NMMA were formed as independent governing & licensing bodies, working with oil companies and engine manufacturers, to establish oil quality standards. Any TC-W3 oil that is licensed by NMMA meets all manufacturers standards and WILL NOT void the OEM warranty.<br /><br />TC-W: This was the first standard established in 1971. The now defunct BIA set it. <br /><br />TC-WII: A new, higher quality of oil was needed as fuel qualities began to deteriorate & higher horsepower engines were becoming commonplace. The NMMA now became the governing body. This standard was set in 1988. <br /><br />TC-W3: Again, declining fuel quality & higher performance engines dictated even higher quality oil. NMMA & manufacturers established this new standard in 1992. <br /><br />TC-W3 Re-certified : One more time. Need for certain additive improvements dictated a re-certification at a slightly higher level. This was set in 1996 .<br /><br /> Ecological Concerns of 2-Cycle Engines & Oil: <br /><br />The following motion was passed at the July 1998 NMMA meeting of the Oil Certification Committee:<br /><br />"The OCC members wish to clarify the OCC position and future plan regarding a standard for eco-friendly two-cycle oils. It appears that additional test work is needed to refine the test methods used to measure biodegradability of two-stroke oils. The OCC has instructed the Environmental Task Force to follow the work underway within ICOMIA, ASTM, CEC, OECD and other technical working groups. Further, it has not been demonstrated that current or future problem with regard to biodegradability. Thus, the OCC shall defer further development of the eco-friendly oil standard until a technical need assessment study is completed and accepted by the OCC.<br /><br />GEAR OILS:<br /><br />There are two types of gear oils. One is for automotive/truck use, the other is for marine use in lower units & stern drives. <br /><br />Organizations: <br /><br />SAE Society of Automotive Engineers<br /><br />API American Petroleum Institute<br /><br />MIL U.S. Military<br /><br />MACK Special Mack truck specs<br /><br />Specifications: <br /><br />MT-1 Newest specification for differentials & transmissions. Supercedes all other specs.<br /><br />GL-5 Predecessor to MT-1.<br /><br />MIL-L-2105D U.S. Military requirement.<br /><br />MACK GO-H/GO-J Special Mack truck spec.<br /><br />Auto/Truck Gear Oil: These oils can be used in differentials, manual transmissions (check OE specs as some late models use Dexron II), and other gearboxes on tractors, garden tillers, etc. There are two different weights available, 80W90 EP & 85W140 EP. Both contain "EP" additives for extreme pressure situations. <br /><br />80W90 EP: A good general-purpose gear lube. For use in "open" (non-limited slip) differentials. Meets/exceeds MT-1, GL-5, MIL-L-2105D & Mack GO-H/GO-J specs. <br /><br />85W140 EP: For extreme performance requirements and wide temperature variations. Withstands severe shock loads & high torque loads. Can also be used in "limited slip" differentials. Meets/exceeds MT-1, GL-5, MIL-L-2105D & Mack GO-H/GO-J specs. <br /><br /> Marine Lower Unit Gear Oils: <br /><br />There are four different types of lower unit/stern drive oils available. In all cases, the boater should check with his OE manual to determine the correct type of oil to use. Due to the environment that these oils perform in, lower unit gear lube should be changed a minimum of once a year, and usually twice. <br /><br />High-Viscosity: This is the most popular type. It is used in all late model (typically mid 70s & up) engines. This is an 80W90 weight oil & carries a GL-5 & MT-1 rating.<br /><br />Type C: This is for older units, most often in electric shift applications. There is no weight rating, as this oil is similar to ATF. <br /><br />Hypoid 90: This is another oil for older units. Most often required in manual shift applications. This is a 90-weight oil. <br /><br />Power Tilt & Trim: While this is not a gear lube, it is related. This hydraulic oil is required in the tilt & trim units on outboards & stern drives which raises & lowers the unit hydraulically. This is a 20 weight, non-detergent oil, and works in all tilt & trim systems. <br /><br />SPECIALTY OILS & LUBRICANTS:<br /><br />Storage:<br /><br />Gas Stabilizer: For storing gasoline in the "off-season". Keeps fuel fresh for up to 12 months. <br /><br />Fogging Oil: Protects internal engine parts from rust & corrosion during "off-season" storage. For use in all 2 & 4-cycle engines.
